Just add back water during the week and kinda monitor the ppm until you figure out what ppm she likes at each stage. If the ppms are going up, you don't need more nutes, you need less. For example, lets say I got a girl and shes at 650 ppms in veg on a fresh res and I come back the next day and its 700, and 730 the day after that.. well, we know she is eating less then 650 to begin with. So you start diluting your res with plain water and get it down to maybe 600 and see what happens. Check it the next day and see if its steady at 600 or still rising... Rinse and repeat until you find the sweet spot. Once you find the spot where it's steady or dropping slightly, you should be golden and the PH should be pretty damn stable. That's pretty much it.